1. Field of the Invention
The present invention relates to a method for producing an electrolytic water whereby the effectiveness of one conventional type of electrolytic water is enhanced and the other type of electrolytic water, conventionally disposed of as virtually useless, is transformed into an electrolytic water which can be effectively used, and to an apparatus for producing the same.
2. Description of the Related Art
An electrolytic water producer has been known which produces an electrolytic acid water and electrolytic alkaline water by electrolyzing water. The main components of the electrolytic water producer are an electrolyzer and a power supply. The inside of the electrolyzer is divided into two areas by a separating membrane, in one area of which a positive electrode is disposed, and in the other area of which a negative electrode is disposed. Applying a current across both of the electrodes in the electrolyzer filled with water produces the electrolytic acid water in the area where the positive electrode is disposed and the electrolytic alkaline water in the area where the negative electrode is disposed.
The electrolytic alkaline water is recognized to be effective for depressing an abnormal intestinal fermentation and is used for a drinking water. The electrolytic acid water is acknowledged to be effective in bactericidal and astringent actions, and is used for cleaning and medical treatment. Thus, each type of electrolytic water has widely been used for enhancing health.
In evaluation of the electrolytic water, the pH value representing hydrogen ion concentration and the residual chlorine concentration have been conventionally used. However, as use of electrolytic water producers has become widespread, even without any significant differences in the pH value or in the residual chlorine concentration of the electrolytic water, differences in electrolytic water effectiveness are noted as dependent on apparatus and region of use.
In the electrolytic alkaline water, when the oxidation reduction potential and dissolved oxygen concentration are low, the water usually displays a high effectiveness for improving health; whereas when the oxidation reduction potential and dissolved oxygen concentration are comparably high, the water shows a low effectiveness for improving health in most cases. A low oxidation reduction potential was considered -50-250 mv, a low dissolved oxygen concentration was considered 4.8-6.8 mg/l, a high oxidation reduction potential was considered +100-+250 mv and a high dissolved oxygen concentration was considered 7-8.2 mg/l.
Accordingly, using an identical service water as the raw water, selecting a model A to produce an electrolytic water with a low oxidation reduction potential and a given pH value, and a model B to produce an electrolytic water with a comparably higher oxidation reduction potential and an identical pH value, a comparison test using rats was made simultaneously with the service water, the electrolytic water produced by the model A, and the electrolytic water produced by the model B by a single testing organization. The test results showed an influence on the gastric mucosal damage, i.e. that the area of erosion on a gastric mucosa tends to become smaller in the following order: electrolytic water produced by the model A, electrolytic water produced by the model B, and service water. A survival test using cancer transplanted immunodefficient mice was made by another testing organization in a similar manner, and the test confirmed a similar tendency in the survival rate.
The oxidation reduction potential and dissolved oxygen concentration of the waters used in these tests were on average: +230 mv, 8.2 mg/l for the service water; -150 mv, 6.2 mg/l for the electrolytic alkaline water produced by the model A; and +75 mv, 7.6 mg/l for the electrolytic alkaline water produced by the model B.
Another test on the survival rate using critical immunodefficient mice made by another organization employed: the service water with a pH of 7.6, an oxidation reduction potential of +520 mv, and a dissolved oxygen concentration of 78 mg/l; a first electrolytic alkaline water C (hereinafter "water C") with a pH of 10.4, an oxidation reduction potential of -485 mv, and a dissolved oxygen concentration of 5.8 mg/l; and a second electrolytic alkaline water D (hereinafter "water D") with a pH of 8.9, an oxidation reduction potential of -309 mv, and a dissolved oxygen concentration of 7.22 mg/l. The test results reported for the survival rate with the service water group, water C group, and water D group were 20.9%, 56.0%, 44.0%, respectively.
According to the aforementioned test results, in the electrolytic alkaline water, as the oxidation reduction potential and dissolved oxygen concentration become lower, the effectiveness becomes higher, indicating need for an apparatus which produces an electrolytic alkaline water with a low oxidation reduction potential and dissolved oxygen concentration, without being subject to influence by the state of the raw water.
The electrolytic acid water, produced as a waste water in producing the electrolytic alkaline water for drinking, is considered to have an astringent action and a bactericidal action. However, its effectiveness is not so apparent as to be really recognized in most cases, and most of such acidic waters are disposed as waste.
When the pH decreases to about 4, the oxidation reduction potential becomes more than +800 mv, and the dissolved oxygen concentration becomes more than 10 mg/l, the electrolytic acid water clearly displays the astringent action when applied to the skin and makes the skin smooth after the water dries. The electrolytic acid water gives the smooth feeling to the skin stronger and longer, as the pH value becomes lower, the oxidation reduction potential becomes higher, and the dissolved oxygen concentration becomes higher. The bacteriostatic effect also has a similar tendency. For example, if the pH value is less than 3.5, the oxidation reduction potential is more than +900 mv, and the dissolved oxygen concentration is more than 12 mg/l, the electrolytic acid water will exhibit such a strong bactericidal activity as to kill most bacteria in a short time even with a dissolved chlorine concentration of about 2 ppm, indicating possible utility as an effective antibacterial agent that does not damage the skin or mocosa.
However, the conventional apparatus can not stably produce an effective acid electrolytic water, because the water quality of the raw water, e.g. service water, changes significantly with the seasons, with temperature, and with time. Furthermore, the conventional apparatus required such maintenance control that an electrolyte solution of a specific concentration always has to be kept so as not to be out of stock.
The raw water fed to the electrolytic water producer sometimes contains free chlorine as hypochlorite, iron rust, and turbidity. In such a case, it is a common practice to pass the raw water through a chlorine remover having a filter for rejecting chlorine of an activated carbon alone or a combination of an activated carbon, hollow fiber membranes and calcium sulfites, and afterward to feed the raw water into the electrolytic water producer. Furthermore, where the major objective is producing an electrolytic water with bactericidal activity, it is also a common practice to add chlorides such as a sodium chloride and/or potassium chloride to the raw water as electrolytes.
There are various types of such apparatus: one type employing a constant current power supply as the power supply to the electrodes in order to stabilize electrolysis; apparatus capable of switching the ranges of a current from a constant current power supply; and apparatus with a pH controller that measures the electric conductivity of an electrolytic water and feeds back the measured result to the electrolyzing power supply.
In the case of the apparatus capable of producing the electrolytic alkaline water for drinking such that the pH value does not exceed 11, the oxidation reduction potential will vary in the range from +150 mv to -250 mv and will be unstable, depending on the potential of the raw water, the gas dissolved in the raw water, the electrolytes contained in the raw water, and the quantity of water treated.
In case of the apparatus provided with the pH controller, it is possible to produce an electrolytic water with a comparably stable pH value; however, the oxidation reduction potential changes significantly, depending on differences in the raw water as in the previous case.
When chlorides are added as electrolytes, it is possible to produce an electrolytic acid water with a low pH value and a high oxidation reduction potential; however, this technique is prone to a high free dissolved chlorine concentration of more than 50-150 ppm and it has proven very difficult to reliably suppress the flee dissolved chlorine concentration to less than a specific limit.
On the other hand, the electrolytic acid water containing free chlorine has a bactericidal effect. For instance, in the treatment of atopic dermatitis with a serious secondary infection, a high chlorine concentration displays a significant effect of skin disinfection. The free dissolved chlorine concentration contained in an electrolytic acid water does not damage a healthy skin up to about 50 ppm; however, if the electrolytic acid water is repeatedly applied several times a day to a skin that is chapped or inflamed or anaphylactic, the electrolytic acid water with a chlorine concentration of more than 25 ppm reportedly causes a slight damage such as eruption owing to irritation. Therefore, the chlorine concentration should be controlled to less than 20 ppm for safety, except for use under supervision of a doctor.
Furthermore, electrolytic alkaline water coproduced with electrolytic acid water having a strong bactericidal effect will sometimes have a high pH value exceeding pH 11 and a low oxidation reduction potential of less than -800 mv. Such an electrolytic alkaline water is rich in metal ions such as sodium and potassium ions derived from electrolytes, and drinking such an electrolytic alkaline water is a danger to one's physical condition and it is very bad tasting. Accordingly, such alkaline water has been disposed as waste, although it can be used for cleaning utensils and the like.
Generally, the quantity of added electrolytes is in the range of 500.+-.200 mg/l as sodium chloride. In the case of chlorine ions as electrolytes contained in the service water as a raw water, the maximum level of chlorine ion content consistent with water quality standards is 200 mg/l (329 mg/l as NaCl). Accordingly, in the electrolyte addition type apparatus also, the quality of the raw water specially significantly influences the oxidation reduction potential and free dissolved chlorine concentration of the electrolytic water thereby produced.
In the conventional apparatus, the electrolysis is conducted in one electrolyzer; and for a raw water of constant quality, the quantity of water to be treated and the amount of current to be applied will determine a quantitative combination of a pH value, oxidation reduction potential, dissolved oxygen concentration, free dissolved chlorine concentration, electric conductivity, and the like. Consequently, it was difficult to simultaneously produce an electrolytic water with a different quantitative combination of these and also difficult to produce an electrolytic alkaline water suitable for drinking and an electrolytic acid water with a bactericidal and bacteriostatic effect.
Furthermore, the conventional apparatus is designed without paying attention to the function of dissolved oxygen and, in fact, the dissolved oxygen concentration of the electrolytic water is completely disregarded.